Protected Function PrintTransitionTable() As String
            'TODO: Display transition functions in tabular format 
            Return ""
End Function

Public Overridable Sub AddStates(ByVal s As String)
            If _states.Contains(s) Then
                Throw New ArgumentException($"The set of states already contains '{s}'.")
            Else
                _states.Add(s)
            End If
End Sub

myDFA = new Codecs.Languages.Regular.DFA();
            myDFA.InputSymbols = new string[2] { "1", "2" };
            myDFA.AddStates(State.StateCollection.Keys.ToArray());
            foreach (KeyValuePair<string,State> item in State.StateCollection)
            {
                StatesViewer.Rows.Add(item.Key, item.Value.m_TargetOne.Name, item.Value.m_TargetZero.Name);
                Codecs.Languages.Regular.TransFunc trans1 = new Codecs.Languages.Regular.TransFunc();
                trans1.PrevState = item.Key;
                trans1.Input = "1";
                trans1.NextState = item.Value.m_TargetOne.Name;
                myDFA.AddTransitions(trans1);
                Codecs.Languages.Regular.TransFunc trans0 = new Codecs.Languages.Regular.TransFunc();
                trans0.PrevState = item.Key;
                trans0.Input = "0";
                trans0.NextState = item.Value.m_TargetZero.Name;
                myDFA.AddTransitions(trans0);
                if (item.Value.IsAccept)
                    myDFA.AddFinalStates(item.Key);
            }
            Codecs.Languages.ContextFree.CFG sa = Codecs.Utils.DFAExtensions.ToCFG(myDFA, "CFG1");
            richTextBox1.Text = myDFA.ToString();
            richTextBox2.Text = sa.ToString();